A walm welcome to you!!!

Let us share something worth that will help all of us to increase our knowledge orientation in the huge and ever expanding world of Networking!

I have created this blog to help each and everyone who visits this blog to get himself acquainted with new technologies, recent developments in the world of technology....

I hope you will help me share my knowledge with you....!!!!

Monday, February 20, 2012

Internet closed on 8th March,2012?

Yes, very true, FBI is closing Internet on 8th March,2012 in more than 100 countries!!

Internet services will be shut down on this very day due to  a disastrous virus that has infected lakhs of computers in more than 100 countries. This virus belongs to the Trojan category and is named as the DNSChanger. When released on the Internet, this virus sends manipulated/fraudulent websites to the web surfers by changing the entries listed in the Domain Name System (DNS).
 Now, Domain Name System (DNS) is a service that converts your domain names (for example, http://www.lifedownloadedfromheavens.blogspot.com into it's IP Address). DNS is the backbone
of the Internet addressing scheme. Imagine, what would be happening if this backbone is affected...

This virus has affected many computers including 500,000 from American continent alone. The FBI
 has shutdown the DNSChanger network, but the solution is only a temporary one. The court has
 ordered a deadline and that's 8th March. Users of Windows & Mac are at a greater risk of this Trojan
since it exploits the browser directly and thereafter your operating system gets infected.

Let me tell you something about rouge DNS Servers. A rouge DNS Server is the one that redirects the
DNS name resolutions to other DNS Servers. This is something difficult to understand, but technical
people would interprete this easily. Imagine that your Mom has given you a 'code' and its meaning is
known to you (that is you are a DNS Server in this case). She has told you to tell that code to your
brother. Now, if you are a rouge DNS Server, you will not tell it to your brother, but you will 'redirect'
that code to your sister. This is also called as DNS Hijacking.

Here's a checklist with the aid of which you can self-check of your computer to make sure you're not infected by comparing your computer's DNS setting to the list of rogue DNS servers: to to to to to to

FBI has also publish an article on this issue and you can read it on this address:

To brief out the process mentioned in the checklist, you can follow the following steps:
(i) Click Start
(ii) Go to Run and type 'cmd'. This opens the command prompt window
(iii) Type 'ipconfig /all'
(iv) In the Local Area Connection details, check the DNS Server Address.
(v) Match it with the above addresses.

I hope you can now safeguard your PC against the above deadly trojan.




Sunday, February 19, 2012

How can a Computer 'DIE'....sounds unbelievable, but true!!! (PART-I:Reasons & Causes)

Death of a Computer!

So, have you ever performed a 'funeral' of your computer? This would be the dumbest question you might have heard in your whole life. Actually, its not that your computer dies, but the 'operating system' residing in your computer gets 'corrupted' due to some or the other reason. In simple words, you may call it that your computer 'crashed'. You might have heard many people speaking about a computer 'crash', and it would be rather true to say that this crash is due to a very critical problem arising in the system. Now, mostly and let me say it generally or technically, this 'crash' is called the 'Blue Screen Error' or the 'Death Screen'.

Mostly, these errors pop up on your computer screen as 'STOP ERRORS'. And when you start watching at your screen making an oval of your mouth, this error becomes a great concern for you. Even sometimes these errors may pop up at the ATMs and you may not be able to withdraw money....and then you start cursing that poor ATM machine! To start with, let me discuss the core reasons for these STOP errors.

Actually, in the real life environment, the causes of these errors might be really difficult to be recognized. If you are using Microsoft Windows XP/Vista/7, then you can view the error 'code' on the blue screen that appears.

Well, can you see the highlighted area in the above image? The 0x0000007B is the error code. Now, following may be the most common reasons for the STOP errors:

(i) Hardware & External Devices: This devices such as the CD-ROM, USB Drives etc., may cause
    such types of errors if they are malfunctioning. Detaching these type of devices without using the
   'Safely remove Hardware' command. Removing such external devices suddenly results in corruption
    of the device and sometimes causes damage to the computer.

(ii) Running lot of programs at the same time: Accepted that a computer is a device that is multitask
    enabled. But, this too, has a limit! If you keep on running many programs, the computer will start
    running out of memory. This will cause the Blue Screen error to pop up. In technical terms, this
    condition  is called the Memory Dump.

(iii) Malfunctioning of Device Drivers: First of all, let me make you understand the term 'driver'.A
    driver is a special 'program' that makes your computer communicate with the hardware or
    external hardware such as the printer, CD-ROM etc. And yes, this thing may be the reason for
    the STOP Error. If your device drivers are corrupted due some or the other reasons, BSE may pop

(iv) Corrupted Startup Files: Now, this is the most concerning reasons of all. If the Operating System
      files are corrupted or are damaged by malicious software or virus attacks, then it may result your
      system to crash unexpectedly. 

(v) BIOS Settings: BIOS (Basic Input/Output System) settings, if configured erroneously, then they
     might result in STOP Errors.

These were the most common reasons for STOP errors to pop up on your computer screen. These
require immediate attention since they are 'critical' and your system cannot function normally due to the damage caused to it.

In the next part, I will be discussing the solutions to the above errors alongwith the error codes,
so stay tuned to my blog!

Thursday, February 16, 2012

OSI, IP Suite & the DoD Model-I (OSI Model)

Now, lets turn to the 'bases' on which the whole Internet functions. These are the core concepts of the 
Internet and one must know how the Internet functions. I have broken the whole post into 
three parts- 
(i) The OSI Model
(ii) The IP Suite
(iii) The DoD Model

I. The OSI Model (Open Systems Interconnection)

1. Introduction
   (i) A networking model introduced by the International Organization for Standardization (ISO)
       to promote multivendor interoperability.
   (ii) OSI is a seven-layered conceptual model consisting of the application, presentation,
        session, transport, network, datalink, and physical layers.

2. Layers of OSI Model as defined by the International Organisation for Standardisation (ISO)

(i) Application Layer

Layer 7 provides an interface between the communications software and any applications
that need to communicate outside the computer on which the application resides. It 
also defines processes for user authentication.               

(ii) Presentation Layer

The presentation layer formats data received from the application layer  before passing
 it to the layers. Encryption also is defined by OSI as a  presentation layer service.

(iii) Sessions Layer

The session layer defines how to start, control, and end conversations (called sessions). 
This includes the control and management of multiple bidirectional messages so
 that the application can be notified if only some of a series of messages are completed.

(iv) Transport Layer

The transport layer works with the network layer to package and transfer data that it 
receives from the session layer. Layer 4 focuses on issues related to data delivery to
another computer error recovery and flow control.

(v) Network Layer

The network layer defines three main features: logical addressing, routing (forwarding)
and path determination. The routing concepts define how devices (typically routers)
forward packets to their final destination. Logical addressing defines how each device 
can have an address that can be used by the routing process. Path determination      
refers to the work done by routing protocols by which all possible routes are learned, but
the best route is chosen for use.

(vi) Data-Link Layer

The data link layer defines the rules (protocols) that determine when a device can send
data over a particular medium. Data link protocols also define the format of a header
and trailer that allows devices attached to the medium to send and receive data 
successfully. The data link trailer, which follows the encapsulated data, typically defines
a Frame Check Sequence (FCS) field, which allows the receiving device to detect the transmission errors

(vii) Physical Layer

This layer typically refers to standards from other organizations. These standards deal 
with the physical characteristics of the transmission medium, including connectors, 
pins, use of pins, electrical currents, encoding, light modulation, and the rules for how to activate and deactivate the use of the physical medium.

I will be again going into the depths of the OSI model, how devices on the network 
operate at different layers of this model in the next few weeks. This was only the overview.
I hope you all atleast got the idea as to what is an OSI model. These layers are so crucial
that no communication can be established over the Internet if anyone of these layers are 
absent (if we take this model into consideration...about IP Suite and DoD Model, I will 
be writing soon).



Wednesday, February 15, 2012

HTTP 503 Error....What the hell!!!!

Another Error....HTTP Error 503: Service Temporarily Unavailable

 Now this really increases the temperature of your brain that it gets ready to blow out of your skull!!!

 Actually, one of my friends is really getting frustrated when she has to see this type of error when she is awaiting for her results on a website (I have never awaited for such things ever in my life!!!!). I
thank her to lot much extents because her query regarding this type of error made me write this post!!!
Alright, jokes apart!!!! Let me give out a detailed description of this type of error with a diagrammatic representation.

I hope you must have read my 'HTTP Error:404' post I wrote on 14th Feb. Now, as we know that
your PC sends a HTTP Get Request to the web server and in turn, the web server sends HTTP Reply
to your PC with code 200 (if it is successful) & 404 (if it wants to irritate you...err...I mean if it
cannot serve your request).

Now, HTTP 503 is a kind of a temporary situation where the server gets overloaded with too many requests (requests from many computers who are trying to access that website). Imagine you are a
server and there are 2 people around you are (computers) asking you some questions. Hmmm, you
can answer them, I think quite comfortably. But imagine there 10 persons (computers) asking you
questions at the same time, you will say 'just shut uppppp!!!! you are making me go out of my senses!!!!!'
The same thing happens with that poor server and when it reaches its limit of its tolerance, then it
 sends you the HTTP 503 error....really poor server...you should feel really sorry for it when you see 503!!!!!

Another reason for this error to pop up on your screen is that the server may be under maintainance
....system administrators might be 'repairing' it. I will not go much into the depth of this 'maintainance' aspect because it will run into pages!!!!

This 503 is a temporary condition, once the traffic to the server reduces or when the server 
maintainance task is complete, it will soon be up.

I hope you will now understand what is 503 error. 

Tuesday, February 14, 2012

HTTP 404 'NOT FOUND'.....One of the most irritating errors in the world!!!!!

What do you mean by HTTP error 404?

Irritating, hopeless, useless....etc, that's what you must be uttering when you have this error on your screen.

But have you ever tried to 'discover' what is this error or why does it pop out, either by Googling it or otherwise?

Hmmm, now let me explain what is this 'irritating' thing....

*click on the image to view it larger

Now, have a look at the above diagram....I will make you understand in a simplest manner....
1. HTTP (Hyper Text Transfer Protocol) is a request-reply protocol (protocol:digital rules that
    enable computer systems to communicate with each other).

2. Imagine that you are using Mozilla Firefox as your Web browser (I will call you person X). When
    you type http://www.abc.com, your web browser uses HTTP to reach to abc.com.

3. Now, a request, called the HTTP Get Request is sent by your Web Browser to get the web page
    from abc.com. In simpler words, your web browser requests the abc.com's server to send you a
    web page.

4. Now, the server located at abc.com sends HTTP Reply message to your PC telling it that whether
    your HTTP Get Request can be served.
    (i) OK: HTTP Request can be served, you receive the abc.com's webpage.....gr8!!!you are
         successful in this case!
    (ii) HTTP 404 'NOT FOUND': Oooopss.....the request cannot be served by abc.com's server.....
         now this is what you term it in simple words 'Irritating'!!!!!!!!!!

5. Lastly, if your request is 'OK' then the reply code is 200 instead of 404.....the only difference is
    that your Web Browser does not show you the 200 code.......hmmm, I wish it would have
    shown....atleast we would have said 'GR8, I received the web page'!!!!!!

I hope you will now understand why you see that 404 error!!!!

Human Brain.....the configured organ!

Have you ever imagined....what is the potential of the thing that is makes you imagine, that makes you think?
Yes, this thing, the human brain is something that is filled with enormous intelligence & is bestowed with abilities to think, innovate & imagine. This is true to science & technology, accounting, architecture, engineering, medical sciences, legal issues and to lot and much more aspects. People, in their own fields keep on innovating and these innovations make that field dynamic.

Secondly, innovations cannot be made without the aid of perspective. Perspective? Rightly, perspective to look at things around is the most crucial aspect. Why are innovators, scientists and other great people who have been bringing revolutions different from us? The reason is simple-their perspective, in other words, how they look at things around them. Why was Newton the only person who thought that there must be some force that must be pulling down an apple which got detached from the tree branch? This was his perspective to look at things. Our perspective-who has time to sit under an apple tree to think about a falling apple?? It is not necessary to 'fetch' time to innovate things, but to look at things more closely and imaging or finding out the reasons as to why a particular thing or a process works in a particular manner.

Capacity of human brain...??? What do you think it might be....is it in megabytes (Mb), Gigabytes (Gb), Terabytes (Tb) or more than that? Hmmm, the answer is not precise, but even where the largest computers have the capacity of 10 to the power of 12, imagine what must be the capacity of the thing that invented these 'largest' computers.

Thinking deeply on a particular aspect requires that part of your brain to be more active. Likewise, when we think that 'My friend is more intelligent in Math than me', we are actually wrong. When human brains are 'manufactured', they are bestowed with the same quantum of intelligence, though there are some exceptions.
But speaking out on general terms, when a person shows his skills in a particular field, we must conclude that his brain is active (configured mainly ) for that particular activity.

Verdict-look out at things with a sharp perspective, get to know about your ability and continue the process of innovations!